In the related art, for example, as a pressure sensor (differential pressure sensor) which detects variation in pressures, a pressure sensor is known which includes an accommodation container having a vent hole, a substrate which is disposed in the accommodation container and has a through-hole or a recessed portion, and a piezoelectric element which is supported to the substrate in a cantilever manner so as to be vibrated in the through-hole or the recessed portion (refer to PTL 1).
By the pressure sensor, the piezoelectric element is vibrated according to a magnitude of a pressure difference between variation in the pressures transmitted to the accommodation container via the vent hole, and a pressure inside the through-hole or the recessed portion following a delay from the variation in the pressures. As a result, the pressure sensor can detect the variation in the pressures transmitted to the accommodation container based on variation in voltages generated in the piezoelectric element.